Twitter users and bloggers have since questioned why Braff, former star of the hugely successful long-running sitcom Scrubs, did not simply use his own cash. Others have questioned whether Wish I Was Here's backers are handing over cash with little prospect of seeing any returns, even if the film triumphs at the box office. LA-based Guardian blogger and film-maker Lisa Marks wrote:

"Is it OK for someone with Braff's financial clout to ask the public for their money? What irks is that the man on the street will not be an investor in the project, merely a donor. So if the movie becomes a sleeper hit like The Blair Witch Project, which was made for $60,000 but grossed $250m worldwide, no donor will see any kind of return. The producers get to build another kidney-shaped swimming pool, but you'll be left with your pdf of the screenplay ($10), frameable art prints ($60) or a fleeting moment as an extra ($2,500)."

Braff, however, told the LA Times critics were mistaken if they thought he had "Oprah Winfrey money". He said: "I've done well in my career, but I am not sitting on $22m. I'm doing this so that one negative audience comment in a test screening won't force me to change the end of my movie."

Braff also denied suggestions that backers would receive little for their support, pointing out that many will have the right to attend early screenings and after-parties. One donor who handed over $10,000 will get a speaking role in the film.

"Even the most entry-level backer will get access to an online magazine about the making of the film," said Braff. "If David Fincher, who I'm a huge fan of, had a video blog of the making of one of his movies, I would have been the first one there.

"People who don't like what I'm doing, that's fine. That's the great thing about crowd-sourcing – it's very pragmatic. You're into it or you're not. There are obviously a lot of people who like the idea and will support it. I feel like we've all joined this little club and we're going to make a movie together."

At time of writing, Braff's film had raised more than $2.24m via Kickstarter, with 25 days of the campaign still to run. The film-maker has admitted to being inspired by the Kickstarter success of a recent campaign for a movie based on the long-running cancelled US detective show Veronica Mars. The latter's Kickstarter raised a record $5.702m (£3.70m), a figure which might yet be within the reach of Wish I Was Here.